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Normative values for ureteral diameter in children
Kumar K Shashi1, Ted Lee2, Sila Kurugol3
1Department of Radiology, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, 02116, USA. drkumargowda@gmail.com.
Insights
This study establishes normative ureteral diameter values for children using MR urography. The average widest internal ureteral diameter in pediatric patients is 3.8 mm, with variations based on age and sex.
Area of Science:
- Pediatric Radiology
- Urology
- Medical Imaging
Background:
- Ureteral assessment is crucial for evaluating urinary tract abnormalities like obstruction and reflux.
- Current imaging practices lack established normative ureteral diameter values for pediatric patients.
- This deficiency hinders accurate diagnosis and management of pediatric urinary tract conditions.
Purpose of the Study:
- To establish age-related normative values for ureteral diameter in pediatric patients.
- To provide a reference standard for interpreting ureteral dimensions in children.
- To aid in the diagnosis of conditions causing abnormal ureteral dilation.
Main Methods:
- Retrospective review of 121 magnetic resonance (MR) urography studies.
- Analysis of 160 normal ureter units using specialized imaging software for maximum internal diameter measurement.
- Calculation of average widest internal ureteral diameter and statistical analysis for age, sex, and laterality associations.
Main Results:
- Ureteral diameter progressively increases with age, from 3.2 mm in infancy to 5.0 mm in adolescents.
- After age 9, males exhibit slightly larger ureteral diameters than females (OR=1.91).
- The right ureter is marginally larger than the left (3.9 mm vs. 3.7 mm).
Conclusions:
- The study provides normative values for average widest internal ureteral diameter in pediatric patients.
- A threshold of 3.8 mm is proposed as the average widest internal ureteral diameter for the pediatric population.
- These findings offer essential reference data for pediatric radiologists and urologists.
Background:
Assessment of the ureter is a fundamental part of the radiologic evaluation of the urinary tract. Abnormal ureteral dilation warrants further investigation to assess the etiology, which includes obstruction and/or reflux. Despite this fundamental need, there are no established normative values in children based on imaging.
Objective:
To provide normative values for ureteral diameter in pediatric patients with age-related ranges.
Materials And Methods:
We retrospectively reviewed all magnetic resonance (MR) urography studies and chose only normal ureters for assessment. The images were analyzed on commercially available software to assess maximum internal diameter. Manual measurements were done in cases where the images were below the resolution for automated assessment. Maximum intraluminal ureteral diameters were measured in upper, mid and lower thirds and the average of the three maximum ureteral diameters was used to obtain the average widest internal ureteral diameter. Multivariable linear regression was performed to test the association between the calculated diameter and gender. Differences in sizes between the left and right ureter were assessed using paired Wilcoxon signed rank test.
Results:
One hundred twenty-one MR urography studies were selected, which included 160 ureter units. The diameter increases progressively with age, ranging from 3.2 mm during infancy to 5.0 mm in patients older than 16 years of age. After 9 years of age, the average widest internal ureteral diameter is slightly larger in males compared to females (odds ratio [OR]=1.91, 95% confidence interval [CI] [1.63, 2.25], P<0.0001). The right ureter was slightly larger than the left (3.9 mm vs. 3.7 mm, P=0.004) among 39 patients in whom both right and left ureter units were included. The average mid ureteral diameter is widest, followed by the distal third then proximal third.
Conclusion:
We present the normative values for the average widest internal ureteral diameter based on laterality and different segments. In the pediatric population, 3.8 mm should be considered the average widest internal ureteral diameter.
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